Efficient sewage purification material based on complex microbial inoculants and preparation method of efficient sewage purification material

Abstract

The invention relates to an efficient sewage purification material based on a complex microbial inoculant and a preparation method of the efficient sewage purification material, and belongs to the technical field of sewage treatment. Alkali bacillus with outstanding stress tolerance constructs a stable and adaptive micro-ecological environment for heterotrophic nitrification compound bacteria and denitrification compound bacteria, ammonia nitrogen can be efficiently converted into nitrate nitrogen and then reduced into nitrogen, the nitrogen removal effect is greatly improved, meanwhile, functional bacteria degrade organic pollutants through metabolism, and the nitrogen removal effect is improved. An adsorption and degradation synergistic mechanism is formed by the microbial inoculum, a porous structure of the modified biochar and rich oxygen-containing functional groups, the biochar firstly efficiently adsorbs heavy metals and refractory organics in sewage, the concentration of pollutants is concentrated to construct an efficient reaction microenvironment, degradation of the organics by the microbial inoculum can effectively avoid adsorption saturation of the biochar, and the microbial inoculum and the biochar supplement each other, so that the biochar can be degraded more efficiently. And finally, synchronous purification of nitrogen and organic matters is achieved, and the method is suitable for removal of ammonia nitrogen in high-salt sewage.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology and relates to a high-efficiency wastewater purification material based on composite bacterial agents and its preparation method. Background Technology

[0002] Compound microbial agents are typically composed of multiple functional strains of bacteria, fungi, and actinomycetes. Through the complementary and co-metabolic effects of different bacterial species' enzyme systems, they can achieve the stepwise decomposition of macromolecular pollutants. Simultaneously, they enhance the synergistic denitrification (nitrification-denitrification) and phosphorus uptake processes by polyphosphate-accumulating bacteria, increasing phosphorus removal rates to over 90% and COD removal rates to over 40% higher than single-agent agents. Currently, the industry is gradually developing an integrated purification system of "compound microbial agent + carrier material." The carrier provides a stable colonization environment for the microbial community, extending the residence time of the microorganisms and enhancing functional synergy. Traditional carrier materials include polypropylene packing, ceramsite, and activated carbon. Polypropylene packing has poor corrosion resistance, with a service life of only 2-3 years in highly acidic and alkaline industrial wastewater, leading to frequent replacements and increased maintenance costs by 40%-60%. Ordinary ceramsite and activated carbon have limited specific surface areas (usually less than 500 m²). 2 / g), with an unreasonable pore structure, low biofilm attachment, and a long biofilm formation period (about 15 days), making it difficult to meet the requirements for efficient treatment.

[0003] Chinese invention patent application CN119371009A discloses a high-efficiency domestic sewage treatment agent and its preparation method. This sewage treatment agent is composed of 60-80 parts of a composite material, 20-40 parts of modified montmorillonite, and 30-50 parts of a composite microbial inoculum. The composite microbial inoculum is composed of Bacillus coagulans, Bacillus cereus, and Trichoderma viride. This water treatment agent uses a combination of physical adsorption, chemical degradation, and biological treatment to deeply purify domestic sewage, effectively improving the removal rates of COD, BOD, and nitrogen and phosphorus, purifying water quality, and increasing water transparency, showing promising market application prospects.

[0004] When treating high-salt industrial wastewater containing halogenated hydrocarbons and benzene compounds, the aforementioned wastewater treatment agents suffer from insufficient efficiency. This is because a high-salt environment disrupts the osmotic pressure balance inside and outside the cells of the microbial strains in the compound microbial solution, causing cell membrane dehydration and shrinkage, loss of permeability, and consequently, metabolic stagnation and functional inactivation of the strains. Furthermore, halogenated hydrocarbons and benzene compounds are highly toxic and can form a synergistic inhibitory effect with high-salt stress, further weakening the strains' ability to degrade the target pollutants, ultimately resulting in a significant decline in overall degradation efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a high-efficiency wastewater purification material based on composite microbial agents and its preparation method. By combining the functions of composite microbial agents and loading them onto a biochar framework material, the wastewater purification efficiency can be improved in a high-salt environment.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A method for preparing a high-efficiency wastewater purification material based on a composite microbial agent includes the following steps:

[0008] Step 1: Inoculate the Alcaligenes bacterium, heterotrophic nitrifying compound bacteria, and denitrifying compound bacteria into the microbial compound culture medium. After cultivation, centrifugation, dilution, and adjustment of the OD of the strains. 600 The value was 1.0, resulting in a mixed bacterial suspension.

[0009] Step 2: Calcine the rice straw, then soak it in calcium nitrate solution and calcine it again to obtain modified biochar. Treat the modified biochar with mixed acid, then ultrasonically mix it with sodium alginate solution and melamine sponge. Crosslink it with calcium chloride to construct channels and obtain the biochar skeleton material.

[0010] Step 3: A polydopamine coating layer is formed by the self-polymerization of dopamine on the surface of the mixed bacterial suspension, and then the bacterial cells are loaded onto the biochar framework material to obtain a high-efficiency wastewater purification material based on composite bacterial agents.

[0011] Furthermore, the alkaloid agent is any one of *Haloxylactobacillus* from the South China Sea sediments and *Haloxylactobacillus* from the ocean.

[0012] These two types of alkali bacteria possess excellent salt and alkali tolerance characteristics, enabling them to survive stably in complex wastewater environments with high salinity. This creates a suitable micro-ecology for functional bacteria and avoids the inhibition of nitrifying and denitrifying bacteria by high salt and alkali conditions.

[0013] Furthermore, the heterotrophic nitrifying compound bacterial agent is a mixture of Pseudomonas aeruginosa and Pseudomonas sphaeroides.

[0014] Furthermore, the denitrifying compound bacterial agent is a mixture of Aeromonas salmonidae and Pseudomonas fluorescens.

[0015] The two types of compound microbial agents complement each other. Heterotrophic nitrifying bacteria can directly utilize organic carbon sources to convert ammonia nitrogen into nitrate nitrogen, while denitrifying bacteria simultaneously reduce nitrate nitrogen into nitrogen gas, avoiding the accumulation of intermediate products. Combined with the stress-resistant protection of Alcaligenes, a complete nitrogen removal closed loop is constructed.

[0016] Furthermore, the specific preparation process of modified biochar is as follows:

[0017] Rice straw was placed in a muffle furnace and calcined at 500-520℃ for 6-8 hours to obtain biochar. The biochar and a 5wt% calcium nitrate solution were added to a reaction vessel and soaked for 2-3 hours. The biochar was then removed, dried, and placed in a muffle furnace. The temperature was increased to 600-620℃ at a rate of 10℃ / min and calcined again for 2-3 hours. The biochar was then ground and sieved to obtain modified biochar.

[0018] The calcination of rice straw to prepare biochar realizes the resource utilization of agricultural waste. Calcium nitrate soaking introduces calcium ions, which not only optimizes the pore structure but also provides sites for subsequent cross-linking. Secondary calcination enhances the mechanical strength and chemical stability of the biochar, preventing it from easily breaking and failing in wastewater.

[0019] Furthermore, the ratio of biochar to calcium nitrate solution is 120-150g: 2-2.4L.

[0020] Ensure that the surface of biochar is fully loaded with calcium ions to guarantee the modification effect.

[0021] Furthermore, the specific preparation process of the biochar framework material is as follows:

[0022] Modified biochar and a mixed acid solution were added to a reactor and stirred at 60-65℃ and 500-600 r / min for 2-3 hours. The mixture was then filtered, washed, and dried. The acid-treated modified biochar was mixed with a 2wt% sodium alginate solution and sonicated for 30-40 minutes. Melamine sponge was then added and sonicated for 90-100 minutes. The mixture was then placed in a 1wt% calcium chloride solution for crosslinking for 24-25 hours. The surface was trimmed, and uniformly distributed cylindrical vertically arranged channels were constructed on the lower surface of the material. The material was then washed and dried to obtain the biochar framework material.

[0023] The mixed acid treatment introduces oxygen-containing functional groups such as carboxyl and hydroxyl groups into the biochar, enhancing its adsorption capacity for heavy metals and organic matter. After ultrasonic mixing with sodium alginate and melamine sponge, it is cross-linked with calcium chloride to form an integrated structure. The 0.1mm diameter vertical channel solves the problem of moisture transmission after the bacterial agent is loaded, avoiding surface drying and bacterial agent inactivation.

[0024] Furthermore, the ratio of modified biochar to mixed acid solution is 50-60g: 400-500mL.

[0025] Furthermore, the ratio of acid-treated modified biochar, sodium alginate solution, melamine sponge, and calcium chloride solution is 8-15g: 500-600mL: 5-9g: 1-1.5L.

[0026] To ensure that all components are fully integrated, the porosity and mechanical strength of the biochar framework are guaranteed, while pore blockage caused by excessive sodium alginate is avoided, thus balancing adsorption performance and mass transfer efficiency.

[0027] Furthermore, the diameter of the vertically arranged cylindrical channels is 0.1 mm.

[0028] Furthermore, the specific preparation process of the high-efficiency wastewater purification material based on composite microbial agents is as follows:

[0029] The mixed bacterial suspension and dopamine were added to a 10 mmol / L Tris-HCl buffer solution and mixed at 30-35℃ and 150-200 r / min for 1.5-2.5 h. After centrifugation, the precipitate was collected. The precipitate and biochar framework material were added to PBS buffer and mixed at 30-32℃ and 150-200 r / min for 45-60 min. After centrifugation, washing, and drying, a high-efficiency wastewater purification material based on the composite bacterial agent was obtained.

[0030] Tris-HCl buffer provides a suitable environment for dopamine self-polymerization. The resulting polydopamine coating not only protects the bacteria from toxic substances in the wastewater, but also enhances the binding force between the bacterial agent and biochar through phenolic hydroxyl groups. PBS buffer maintains the activity of the bacterial agent, ensuring that its function is not lost during loading.

[0031] Furthermore, the ratio of the mixed bacterial suspension, dopamine, and Tris-HCl buffer is 200-300 mL: 2-4 g: 1-1.5 L.

[0032] Ensure uniform polydopamine coating and appropriate bacterial agent loading density to guarantee purification activity without clogging biochar pores, achieving synergistic effects of adsorption and degradation.

[0033] Furthermore, the ratio of precipitate, biochar framework material, and PBS buffer is 0.3-0.6g: 6-10g: 800-1000mL.

[0034] A high-efficiency wastewater purification material based on composite bacterial agents is prepared by the above-mentioned preparation method of high-efficiency wastewater purification material based on composite bacterial agents.

[0035] The beneficial effects of this invention are:

[0036] 1. This invention loads a mixed bacterial suspension onto a biochar framework material to achieve comprehensive purification of complex pollutants. The highly resilient Alkalibacillus provides a stable and suitable micro-ecological environment for heterotrophic nitrifying and denitrifying bacteria, which can efficiently convert ammonia nitrogen into nitrate nitrogen and then reduce it back to nitrogen gas, significantly improving nitrogen removal efficiency. At the same time, the functional bacteria degrade organic pollutants through metabolism, forming a synergistic mechanism of adsorption and degradation with the porous structure and abundant oxygen-containing functional groups of the modified biochar. The biochar first efficiently adsorbs heavy metals and recalcitrant organic matter in the wastewater, concentrating the pollutant concentration to construct a highly efficient reaction microenvironment. Meanwhile, the degradation of organic matter by the bacterial agent can effectively prevent biochar adsorption saturation. The two complement each other, ultimately achieving simultaneous purification of nitrogen and organic matter, and is suitable for the removal of ammonia nitrogen in high-salt wastewater.

[0037] 2. This invention modifies biochar with calcium nitrate, introducing functional ions that optimize its pore structure and provide key sites for subsequent cross-linking reactions. Combined with a size-fitting melamine sponge structure, after thorough mixing and cross-linking, a porous framework is formed. The uniformly distributed, vertically arranged cylindrical channels effectively solve the problem of moisture transfer after bacterial agent loading, preventing the bacterial agent surface from drying out. The polydopamine coating not only protects the bacteria from toxic substances but also enhances the binding force between the bacterial agent and biochar through surface functional groups, significantly reducing the risk of bacterial agent shedding. The appropriate ratio of bacterial agent to biochar ensures that the bacterial agent is evenly distributed inside and outside the biochar pores, ensuring purification activity without clogging mass transfer channels. This results in a high-efficiency wastewater purification material with high mechanical strength, stable load capacity, and high mass transfer efficiency.

[0038] 3. The salt and alkali resistance of the Alkalibacillus in the mixed bacterial suspension of this invention, combined with the protective effect of the polydopamine coating, significantly improves the activity and durability of the bacterial agent in complex wastewater environments. The biochar, after secondary calcination and cross-linking treatment, has excellent mechanical strength and chemical stability and can withstand a certain range of temperature fluctuations. The conditions of each link are highly synergistic, and the mild reaction range avoids the inactivation of the bacterial agent due to environmental changes. The acid-base regulation effect of the buffer solution and biochar enables the system to operate stably in wastewater with different pH values. Combined with the water transport guarantee of the efficient water conveyance channel, the adaptability of the material in complex scenarios such as low water level and high salt is further broadened.

[0039] 4. This invention uses rice straw as raw material to prepare biochar, transforming agricultural waste into a high-value purification carrier and effectively reducing resource waste. Subsequent modification and construction steps utilize environmentally friendly reagents, and no toxic or harmful substances are generated in any reaction step. The washing wastewater can be discharged after simple treatment, posing no risk of secondary pollution. Simultaneously, the synergistic recycling of each component significantly reduces operating costs: the biochar framework is reusable, and the polydopamine coating and biochar loading together extend the activity cycle of the microbial agent, reducing the frequency of agent replenishment. The entire process does not require extreme conditions such as high temperature and high pressure, resulting in low energy consumption and fully meeting the application requirements for green and environmentally friendly solutions. Detailed Implementation

[0040] To further illustrate the technical means and effects of the present invention in achieving the intended purpose, the following detailed description of the specific implementation methods, features and effects of the present invention, in conjunction with preferred embodiments, is provided below.

[0041] Example 1: This example provides a high-efficiency wastewater purification material based on a composite microbial agent, which is prepared through the following steps:

[0042] S1: Halalkalibacter nanhaiisediminis (a type of halophilic bacteria found in sediments of the South China Sea), heterotrophic nitrifying compound bacteria (Pseudomonas poae and Pseudomonas peli in a 1:1 volume ratio), and denitrifying compound bacteria (Aeromonas assalmonicida and Pseudomonas fluorescens in a 1:1 volume ratio) were inoculated into 125 mL of microbial compound culture medium at inoculation rates of 3%, 3%, and 4%, respectively. The medium was incubated at 25℃ and 180 rpm for 49 h. After centrifugation at 4500 rpm for 11 min, the cell pellet was diluted with sterile physiological saline, centrifuged again to remove nutrients from the culture medium, and finally, the OD of the strain was adjusted with physiological saline. 600 The optical density value at a wavelength of 600 nm was 1.0, resulting in a mixed bacterial suspension.

[0043] S2: 650g of rice straw was chopped, dried, and placed in a muffle furnace. It was calcined at 510℃ for 7 hours to obtain biochar. 135g of biochar and 2.2L of 5wt% calcium nitrate solution (purchased from Guangdong Daxiao Chemical Co., Ltd.) were added to the reaction vessel and soaked for 2.5 hours. The biochar was then removed, dried at 107℃ to constant weight, and placed in a muffle furnace. The temperature was increased to 610℃ at a rate of 10℃ / min and calcined again for 2.5 hours. The biochar was then ground and passed through a 100-mesh sieve to obtain modified biochar.

[0044] S3: Add 55g of modified biochar and 450mL of mixed acid solution (nitric acid and hydrogen peroxide in a 1:1 volume ratio) to the reactor. Stir at 62℃ and 550r / min for 2.5h. Filter, and wash the filter cake repeatedly with ultrapure water and anhydrous ethanol until the pH is neutral. Dry the cake. Mix 11.5g of acid-treated modified biochar with 550mL of 2wt% sodium alginate solution (purchased from Tianjin Damao Chemical Plant) and sonicate for 35min. Add 7g of melamine sponge with dimensions of 1cm×1cm×1cm (purchased from Shanghai Beiyou Building Materials Co., Ltd.), sonicate for 95min, then place in 1.25L of 1wt% calcium chloride solution (purchased from Tianjin Damao Chemical Plant) for crosslinking for 24.5h, trim the surface, and construct uniformly distributed cylindrical vertically arranged channels with a diameter of 0.1mm on the lower surface of the material. Rinse 4 times with ultrapure water, and bake at 37.5℃ for 10h to obtain the biochar skeleton material.

[0045] S4: 250 mL of mixed bacterial suspension and 3 g of dopamine were added to 1.25 L of 10 mmol / L Tris-HCl buffer (pH 8.5). The mixture was stirred at 32.5 °C and 175 r / min for 2 h. Dopamine self-polymerized on the bacterial surface to form a polydopamine coating layer. The mixture was centrifuged at 6500 r / min for 11 min, and the precipitate was collected. 0.45 g of the precipitate and 8 g of biochar framework material were added to 900 mL of PBS buffer (pH 7.2). The mixture was stirred at 31 °C and 175 r / min for 52.5 min, centrifuged at 7000 r / min for 11 min, washed 4 times with deionized water, and dried at 32.5 °C for 13 h to obtain a high-efficiency wastewater purification material based on the composite bacterial agent.

[0046] Example 2: This example provides a high-efficiency wastewater purification material based on a composite microbial agent, which is prepared through the following steps:

[0047] S1: Halalkalibacter nanhaiisediminis (a type of halophilic bacteria found in sediments of the South China Sea), heterotrophic nitrifying compound bacteria (Pseudomonas poae and Pseudomonas peli in a 1:1 volume ratio), and denitrifying compound bacteria (Aeromonas assalmonicida and Pseudomonas fluorescens in a 1:1 volume ratio) were inoculated into 100 mL of microbial compound culture medium at inoculation rates of 3%, 3%, and 4%, respectively. The medium was incubated at 20℃ and 160 rpm for 48 h. After centrifugation at 4000 rpm for 10 min, the cell pellet was diluted with sterile physiological saline, centrifuged again to remove nutrients from the culture medium, and finally, the OD of the strain was adjusted with physiological saline. 600 The optical density value at a wavelength of 600 nm was 1.0, resulting in a mixed bacterial suspension.

[0048] S2: After 500g of rice straw was chopped and dried, it was placed in a muffle furnace and calcined at 500℃ for 6h to obtain biochar. 120g of biochar and 2.0L of 5wt% calcium nitrate solution (purchased from Guangdong Daxiao Chemical Co., Ltd.) were added to the reaction vessel and soaked for 2h. After removal, it was dried at 105℃ to constant weight and then placed in a muffle furnace. The temperature was increased to 600℃ at a rate of 10℃ / min and calcined for 2h. After grinding, it was passed through a 100-mesh sieve to obtain modified biochar.

[0049] S3: Add 50g of modified biochar and 400mL of mixed acid solution (the volume ratio of nitric acid and hydrogen peroxide is 1:1) to the reactor, stir for 2h at 60℃ and 500r / min, filter, and repeatedly wash the filter cake with ultrapure water and anhydrous ethanol until the pH value is neutral. Dry it, mix 8g of acid-treated modified biochar with 500mL of 2wt% sodium alginate solution (purchased from Tianjin Damao Chemical Plant), sonicate for 30min, then add 5g of 1cm×1cm×1cm melamine sponge (purchased from Shanghai Beiyou Building Materials Co., Ltd.), sonicate for 90min, and then place it in 1L of 1wt% calcium chloride solution (purchased from Tianjin Damao Chemical Plant) for crosslinking for 24h. Trim the surface and construct uniformly distributed cylindrical vertically arranged channels with a diameter of 0.1mm on the lower surface of the material. Rinse three times with ultrapure water and bake at 35℃ for 8h to obtain the biochar skeleton material.

[0050] S4: Add 200 mL of mixed bacterial suspension and 2 g of dopamine to 1 L of 10 mmol / L Tris-HCl buffer (pH 8.5), mix at 30 °C and 150 r / min for 1.5 h. Dopamine self-polymerizes on the bacterial surface to form a polydopamine coating layer. Centrifuge at 6000 r / min for 10 min, collect the precipitate, add 0.3 g of precipitate and 6 g of biochar framework material to 800 mL of PBS buffer (pH 7.2), mix at 30 °C and 150 r / min for 45 min, centrifuge at 6000 r / min for 10 min, wash three times with deionized water, and dry at 30 °C for 12 h to obtain a high-efficiency wastewater purification material based on composite bacterial agent.

[0051] Example 3: This example provides a high-efficiency wastewater purification material based on a composite microbial agent, which is prepared through the following steps:

[0052] S1: Halalkalibacter nanhaiisediminis (a type of halophilic bacteria found in sediments of the South China Sea), heterotrophic nitrifying compound bacteria (Pseudomonas poae and Pseudomonas peli in a 1:1 volume ratio), and denitrifying compound bacteria (Aeromonas assalmonicida and Pseudomonas fluorescens in a 1:1 volume ratio) were inoculated into 150 mL of microbial compound culture medium at inoculation rates of 3%, 3%, and 4%, respectively. The medium was incubated at 30℃ and 200 rpm for 50 h, centrifuged at 5000 rpm for 12 min, and the resulting cell pellet was diluted with sterile physiological saline, then centrifuged again to remove nutrients from the culture medium. Finally, the OD of the strain was adjusted with physiological saline.600 The optical density value at a wavelength of 600 nm was 1.0, resulting in a mixed bacterial suspension.

[0053] S2: 800g of rice straw was chopped, dried, and placed in a muffle furnace. It was calcined at 520℃ for 8 hours to obtain biochar. 150g of biochar and 2.4L of 5wt% calcium nitrate solution (purchased from Guangdong Daxiao Chemical Co., Ltd.) were added to the reaction vessel and soaked for 3 hours. The biochar was then removed, dried at 110℃ to constant weight, and placed in a muffle furnace. The temperature was increased to 620℃ at a rate of 10℃ / min and calcined for 3 hours. The biochar was then ground and passed through a 100-mesh sieve to obtain modified biochar.

[0054] S3: Add 60g of modified biochar and 500mL of mixed acid solution (the volume ratio of nitric acid and hydrogen peroxide is 1:1) to the reactor, stir for 3h at 65℃ and 600r / min, filter, and repeatedly wash the filter cake with ultrapure water and anhydrous ethanol until the pH value is neutral. Dry it, mix 15g of acid-treated modified biochar with 600mL of 2wt% sodium alginate solution (purchased from Tianjin Damao Chemical Plant), sonicate for 40min, then add 9g of 1cm×1cm×1cm melamine sponge (purchased from Shanghai Beiyou Building Materials Co., Ltd.), sonicate for 100min, and then place it in 1.5L of 1wt% calcium chloride solution (purchased from Tianjin Damao Chemical Plant) for crosslinking for 25h. Trim the surface and construct uniformly distributed cylindrical vertically arranged channels with a diameter of 0.1mm on the lower surface of the material. Rinse with ultrapure water 5 times and bake at 40℃ for 12h to obtain the biochar skeleton material.

[0055] S4: Add 300 mL of mixed bacterial suspension and 4 g of dopamine to 1.5 L of 10 mmol / L Tris-HCl buffer (pH 8.5), mix at 35 °C and 200 r / min for 2.5 h. Dopamine self-polymerizes on the bacterial surface to form a polydopamine coating layer. Centrifuge at 7000 r / min for 12 min, collect the precipitate, add 0.6 g of precipitate and 10 g of biochar framework material to 1000 mL of PBS buffer (pH 7.2), mix at 32 °C and 200 r / min for 60 min, centrifuge at 8000 r / min for 12 min, wash 5 times with deionized water, and dry at 35 °C for 14 h to obtain a high-efficiency wastewater purification material based on composite bacterial agent.

[0056] Example 4: This example provides a high-efficiency wastewater purification material based on composite bacterial agents. The difference from Example 1 is that in step S1, *Haloxylactobacillus aquaticus* is used instead of *Haloxylactobacillus salina* from the South China Sea sediments.

[0057] Example 5: This example provides a high-efficiency wastewater purification material based on composite bacterial agents. The difference from Example 1 is that in step S3, a 0.6 mol / L citric acid solution is used instead of the mixed acid solution.

[0058] Example 6: This example provides a high-efficiency wastewater purification material based on composite microbial agents. The difference from Example 1 is that the inoculation amounts of Alcaligenes, heterotrophic nitrification composite microbial agents, and denitrification composite microbial agents in step S1 are 4%, 4%, and 3%, respectively.

[0059] The accession numbers of the strains used in Examples 1-6 are as follows:

[0060] Haematobacterium halophilum from sediments in the South China Sea (deposited at China General Microbiological Culture Collection Center, accession number CGMCC 1.10116).

[0061] *Haloxylactobacillus aquaticus* (deposited at China General Microbiological Culture Collection Center, bioaccession number CGMCC1.12347).

[0062] Pseudomonas aeruginosa (deposited at China General Microbiological Culture Collection Center, bioaccession number CGMCC1.10779).

[0063] Pseudomonas sphaeroides (deposited at China General Microbiological Culture Collection Center, bioaccession number CGMCC1.8857).

[0064] Aeromonas salmonii (deposited at China General Microbiological Culture Collection Center, bioaccession number CGMCC1.16014).

[0065] Fluorescent Pseudomonas (deposited at China General Microbiological Culture Collection Center, bioaccession number CGMCC1.1823).

[0066] Comparative Example 1: This comparative example provides a high-efficiency wastewater purification material based on composite bacterial agents. The difference from Example 1 is that biochar (commercially available, purchased from Zhengzhou Jinbang Environmental Protection Technology Co., Ltd.) is used instead of biochar skeleton material in step S4.

[0067] Comparative Example 2: This comparative example provides a high-efficiency wastewater purification material based on composite bacterial agents. The difference from Example 1 is that the alkali bacillus agent is removed in step S1.

[0068] Comparative Example 3: This comparative example provides a high-efficiency wastewater purification material based on composite bacterial agents. The difference from Example 1 is that in step S4, the modified biochar prepared in step S2 is used instead of the biochar skeleton material.

[0069] The high-efficiency wastewater purification materials based on composite bacterial agents prepared in Examples 1-6 and Comparative Examples 1-3 were subjected to performance testing:

[0070] Wastewater from a chemical plant was used as the research object. The wastewater quality was as follows: ammonia nitrogen content was 539 mg / L, total nitrogen content was 649 mg / L, COD content was 741 mg / L, carbon-to-nitrogen ratio was 1.14, and salinity was 2.6%. The pH of the wastewater was adjusted to 7-8, the temperature was controlled at 30℃, and a sample of high-efficiency wastewater purification material based on compound bacterial agents was added. After 4 days of treatment, the quality of the treated wastewater was measured. Removal rate (%) = (content of substances before treatment - content of substances after treatment) / content of substances before treatment × 100%.

[0071] The test results are shown in the table below:

[0072] Table 1 Performance Test Overview

[0073] project Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Ammonia nitrogen removal rate (%) 92.3 90.7 93.1 91.8 92.6 89.5 76.2 78.4 75.9 Total nitrogen removal rate (%) 88.5 86.9 89.2 87.7 88.9 85.3 69.3 71.5 68.7 COD removal rate (%) 83.2 83.2 86.4 84.9 86.1 82.8 65.4 67.2 64.8

[0074] As shown in Table 1, the ammonia nitrogen removal rate, total nitrogen removal rate, and COD removal rate of Examples 1-6 were all higher than those of Comparative Examples 1-3. This may be due to the synergistic effect of the combined functions of the compound bacterial agent and the biochar framework material. *Haloxylactobacillus* or *Haloxylactobacillus natans* from the South China Sea sediments possess extremely strong salt and alkali tolerance, allowing them to survive stably in high-salinity wastewater. Their metabolic processes can regulate the pH and osmotic pressure of the microenvironment, creating a suitable living environment for heterotrophic nitrifying and denitrifying bacteria, and avoiding the inhibition of functional bacteria activity by high-salt and toxic pollutants. Furthermore, the biochar, after being leached with calcium nitrate... After being treated with foam and mixed acid, the surface forms abundant oxygen-containing functional groups such as carboxyl and hydroxyl groups, and the pore structure is optimized. The uniformly distributed cylindrical vertical channels on the biochar skeleton material form a water transport network, continuously providing moisture to the bacterial agent. The porous structure of the biochar skeleton and the three-dimensional network of melamine sponge work together to provide stable colonization sites for the bacterial agent, reducing the loss of the bacterial agent in sewage. At the same time, the polydopamine coating layer forms covalent bonds with the functional groups on the biochar surface through phenolic hydroxyl groups, which makes the bacterial agent firmly attached to the carrier surface, prolonging the residence time of the bacterial agent in the system and enhancing the functional synergy effect.

[0075] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0076] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for preparing a high-efficiency wastewater purification material based on a composite microbial agent, characterized in that, Includes the following steps: Step 1: Inoculate the Alcaligenes bacterium, heterotrophic nitrifying compound bacteria, and denitrifying compound bacteria into the microbial compound culture medium. After cultivation, centrifugation, dilution, and adjustment of the OD of the strains. 600 The value was 1.0, resulting in a mixed bacterial suspension; Step 2: Calcine the rice straw, then soak it in calcium nitrate solution and calcine it again to obtain modified biochar. Treat the modified biochar with mixed acid, then ultrasonically mix it with sodium alginate solution and melamine sponge. Crosslink it with calcium chloride to construct channels and obtain the biochar skeleton material. Step 3: A polydopamine coating layer is formed by the self-polymerization of dopamine on the surface of the mixed bacterial suspension, and then the bacterial cells are loaded onto the biochar framework material to obtain a high-efficiency wastewater purification material based on composite bacterial agents.

2. The method for preparing a high-efficiency wastewater purification material based on a composite microbial agent according to claim 1, characterized in that, The alkaloid bacterium is one of the alkaloid bacterium found in sediments of the South China Sea and the oceanic alkaloid bacterium. The heterotrophic nitrifying compound bacterial agent is a mixture of Pseudomonas aeruginosa and Pseudomonas sphaeroides; The denitrifying compound bacterial agent is a mixture of Aeromonas salmonidae and Pseudomonas fluorescens.

3. The method for preparing a high-efficiency wastewater purification material based on a composite microbial agent according to claim 1, characterized in that, The specific preparation process of the modified biochar is as follows: Rice straw was placed in a muffle furnace and calcined at 500-520℃ for 6-8 hours to obtain biochar. The biochar and a 5wt% calcium nitrate solution were added to a reaction vessel and soaked for 2-3 hours. The biochar was then removed, dried, and placed in a muffle furnace. The temperature was increased to 600-620℃ at a rate of 10℃ / min and calcined again for 2-3 hours. The biochar was then ground and sieved to obtain modified biochar.

4. The method for preparing a high-efficiency wastewater purification material based on a composite microbial agent according to claim 3, characterized in that, The ratio of biochar to calcium nitrate solution is 120-150g: 2-2.4L.

5. The method for preparing a high-efficiency wastewater purification material based on a composite microbial agent according to claim 1, characterized in that, The specific preparation process of the biochar framework material is as follows: Modified biochar and mixed acid solution were added to a reactor and stirred at 60-65℃ and 500-600 r / min for 2-3 h. After filtration, washing, and drying, the acid-treated modified biochar was mixed with a 2 wt% sodium alginate solution and sonicated for 30-40 min. Then, melamine sponge was added and sonicated for 90-100 min. Finally, the mixture was placed in a 1 wt% calcium chloride solution for crosslinking for 24-25 h. The surface was then trimmed, washed, and dried to obtain the biochar framework material.

6. The method for preparing a high-efficiency wastewater purification material based on a composite microbial agent according to claim 5, characterized in that, The ratio of the modified biochar to the mixed acid solution is 50-60g: 400-500mL; The ratio of the acid-treated modified biochar, sodium alginate solution, melamine sponge, and calcium chloride solution is 8-15g: 500-600mL: 5-9g: 1-1.5L.

7. The method for preparing a high-efficiency wastewater purification material based on a composite microbial agent according to claim 1, characterized in that, The specific preparation process of the high-efficiency wastewater purification material based on composite bacterial agents is as follows: The mixed bacterial suspension and dopamine were added to a 10 mmol / L Tris-HCl buffer solution and mixed at 30-35℃ and 150-200 r / min for 1.5-2.5 h. After centrifugation, the precipitate was collected. The precipitate and biochar framework material were added to PBS buffer and mixed at 30-32℃ and 150-200 r / min for 45-60 min. After centrifugation, washing, and drying, a high-efficiency wastewater purification material based on the composite bacterial agent was obtained.

8. The method for preparing a high-efficiency wastewater purification material based on a composite bacterial agent according to claim 7, characterized in that, The ratio of the mixed bacterial suspension, dopamine, and Tris-HCl buffer is 200-300 mL: 2-4 g: 1-1.5 L.

9. The method for preparing a high-efficiency wastewater purification material based on a composite microbial agent according to claim 7, characterized in that, The ratio of the precipitate, biochar framework material, and PBS buffer is 0.3-0.6g: 6-10g: 800-1000mL.

10. A high-efficiency wastewater purification material based on a composite microbial agent, characterized in that, The material is prepared by any one of the methods described in claims 1-9 for preparing a high-efficiency wastewater purification material based on a composite microbial agent.